1. Field of the Invention
The present invention relates to an antenna structure and related wireless communication apparatus, and more particularly, to an antenna structure and related wireless communication apparatus for adjusting impedance matching and radiation patterns by using an overlapped portion overlapped by a loop structure of a grounding element and a radiation element at a designated distance from the radiation element.
2. Description of the Prior Art
As wireless telecommunication develops with the trend of micro-sized mobile communications products, the location and the space arranged for antennas becomes increasingly limited. Therefore, built-in micro antennas have been developed. Some micro antennas such as chip antennas and planar antennas are commonly used and occupy very small volume.
The planar antenna has the advantages of small size, light weight, ease of manufacturing, low cost, high reliability, and can also be attached to the surface of any object. Therefore, micro-strip antennas and printed antennas are widely used in wireless communication systems. For example, monopole antennas or dipole antennas are suited for use in 3G transceivers.
However, the conventional monopole antenna is a linear antenna, wherein its radiation pattern cannot be centered upwards and its half power beam-width is smaller than 120 degrees. The monopole antenna is unable to fill demands for 3G specifications such as global positioning system (GPS), under certain conditions. Therefore, how to reduce sizes of the antennas, improve antenna efficiency, improve radiation patterns, and increase bandwidths of the antennas become important topics in this field.